The present invention relates to an inspecting method for inspecting the appearance, for example, processing irregularity of the surface of an object such as electronic parts, e.g. capacitors and a distance measuring method used for the inspecting method.
A specific example of a previously used appearance inspecting method will be described.
A UF capacitor is a kind of chip capacitor, which is applied with an ultraviolet curing resin on the surface thereof (referred to as an applied surface) coming in contact with a substrate when mounted, for the purpose of insulation and protection. If the resin is not applied sufficiently, the capacitor is judged to have poor wetting. A region of the capacitor where the resin is fully applied is called a wetting part, and a region thereof where the resin is not applied enough is called a poor wetting part. In the conventional example, the whole area of the poor wetting part is calculated and it is assumed that when the size of the area of the poor wetting part is within a predetermined allowable value, the capacitor is decided to be acceptable. On the other hand, if the size exceeds the predetermined allowable value, the capacitor is decided to be unacceptable.
According to a conventional method, however, the acceptability of the applied surface of the UF capacitor is determined based only by the size of the whole area of the poor wetting part, and the resulting decision may be different from the decision an operator would make. For example, in FIGS. 11A and 11B wherein reference numerals 31 and 33 denote wetting parts and 32 and 34 denote poor wetting parts, assuming the size of the area of the poor wetting part 32 in FIG. 11A is larger than a predetermined value it is decided that it is unacceptable and an operator would judge similarly. On the other hand, assuming the size of the area of the poor wetting part 34 in FIG. 11B is also larger than the predetermined value, it is decided that it is unacceptable, but the decision of the operator would acceptable because the actual poor wetting part is very small at the periphery of the UF capacitor.